Telephone system



Dec. 30, 1941.

W. A. RHODES TELEPHONE SYSTEM y 9 Sheets-Sheet 2 Filed Sept. 20, 1940THOUSANDS /NVENTOR n/.ARHODES AHORA/Ev;Y

Dec. 30, 1941. w. A. RHODES TELEPHONE SYSTEM Filed Sept. 20, 1940 9Sheets-Sheet 3 TAB. I

HUNDREDS Afro/mfr DeC. 30, 1941. W A RHODES TELEPHONE SYSTEM Filed Sept.20, 1940 9 Sheets-Sheet 4 hHG. 4 A TAB- 1I 7499 XX OO INVENTOR W. A RHODE 5 AHORA/5y Dec. 30, 1941. w. A. RHoDEs 2,267,950

TELEPHONE SYSTEM Filed Sept. 20, 1940 9 Sheets-Sheet 5 /NVENTORn/.ARHODES ATTORNF V 9 Sheets-Sheet 6 /NVENTOR y WARHODES ATTORNEY w. A.RHODES TELEPHONE SYSTEM Filed sept. 2o, 19210 XXON XXIN l XXOW XXQ lXXO...

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Dec. 30, 1941.

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|. omxx /NVENTOR WA .RHODES Dec. 30, 1941. w. A. RHODES TELEPHONE'SYSTEM F11-ed sept. 20, 1940 9 'sheets-sheet 9 mmxx lmoxx mwxxl mexxmix lmoxx @xx l oxx /Nl/ENTOR WA. RHODE 5 AT TORNEV Patented Dec. 30,1941 2,267,950 TELEPHONE SYSTEM william A. Rhodes, New Lab BellTelephone York, N. Y., assignor to oratories, Incorporated,

New York, N. Y., a corporation of New York Application September 20,

Claims.

. This invention relates to telephone systems and more particularly tothose systems in which the numerical indication of a calling line isautomatically determined and made available.

It is well known that in certain types of telephone connections such asthose, for instance, in which the calling line is extended automaticallyor otherwise to some remote station, it is necessary to ascertain thenumber of the calling station in order that charges for the call may beproperly assessed to said station. Such connections are known as toll orlong distance connections and in some types of automatic telephonesystems in which the calling line is routed to its destination via theposition of a recording operator where, after cated to the operator bythe calling subscriber, said number is verified over a so-calledchecking multiple. This verification is made by touching the tip of achecking cord to that pin in a s0- called checking multiple which isassigned to the given number and if the number as given by the 1940,Serial No. 357,518

the number has been communi- Y calling party is correct, a tone circuitis completed over the checking cord which is heard in the operatorstelephone set. On the other hand, if the number as given does notcorrespond to that of the pin to which the tip of the checking cord istouched, the tone circuit is not completed, and this fact indicates tothe operator that the number given by the caller does not correspond tothat of the station from which'he is calling, in which event service maybe denied until the discrepancy is rectied.

In automatic telephone systems, it lis desirable to have the identity ofthe calling station ascertained and transmitted automatically to somepoint at which it may be recorded on settable registers for the visualdisplay of the number,

if the call is completed through an operators position, or for automaticrecording if the information is to be utilized for operating printing orother recording devices responsive to the setting of the registers. y

My invention is principally concerned with the automatic identificationof the calling line number and its principal feature is an arrangementof two main groups of vacuum tube devices and two auxiliary groups ofvacuum tube devices which are arranged with respect to each other,respectively, to-.produce to coordinate translations of which the i'lrstprovides an identification of each of the -rst two digits of the linenumber and t-he second provides an identication of each of the secondtwo digits ofthe line number. According to one embodiment of myinvention as adapted to provide identification for one or more lines ina ten thousand line capacity telephone ofce, I propose to use two maingroups of four hundred vacuum tubes each having twenty-ve anodes, witheach line to be identified connected to one anode in a tube of each maingroup, and two auxiliary groups of eight other vacuum tubes, each havingforty anodes with each anode connected to a source of positive potentialand to the grid of a tube in the correlated main group according toalternating potentials of predetermined frequencies which are toactivate the tubes in the two main groups to produce certain signalcurrents which are distinctive for the four digits of the twenty-ve linenumbers of the corresponding lines connected to the anodes of saidtubes.

Each of the grids of the auxiliary tubes is connected-to a source ofalternating current cf a specific frequency and since the cathodes areall connected to a source of filament current and their anodes to asource of positive potential in the known manner, said tubes arenormally ac- 'tivated to modulate the anode potential with one or morefrequencies, which potential is transmitted through appropriate couplingto the grids of the respective tubes in the main groups to which suchanodes are connected. Inasmuch as the anodes of the tubes in each of themain groups are at negative potential when none of the lines connectedthereto are calling,v the potential to which the main tube gridsareraised by the operation of the auxiliary tubes is productive of noeffect. However, when a line calls, the potential of its anode in eachtube in the two main groups of tubes to which such line is connected ischanged from negative to positive and is of such a value that, with'thegrid potential determined by the operation of the auxiliary tube ortubes from which said potential is derived, the two tubes in the maingroups are rendered conducting, thereby completing a current flowthroughtheir respective anodes which is deter mined by the frequenciesthat activate the auxiliary tubes from which the grids of the operatedmain tubes derived their activating potentials. Since each of the maintubes bears a digital coordinate relation to the twenty-five linesconnected to its respective anodes, and since the connection between thegrids of the main tubes and the anodes of the auxiliary tubes isAdetermined by al certain frequency allocation to each numeral of adigit, there is presenti in the anode current of the two operated tubesin the main groups a plurality of distinct signals which singly ber.These signals be displayed or recorded by appropriate apparatus providedfor the purpose.

A clearer conception of the scope and purpose of the invention may beobtained from the following description, appended claims and attacheddrawings. in which:

Fig. 1 shows a partial diagrammatic layout of an automatic telephoneline extension and the receiving equipment of the line identificationcircuit;

Figs. 2 and 3 show,v in part, one of the two main groups of tubes;

Figs. 4 and 5 show, in part, the other of the two main groups of tubes;

Figs. 6 and 7 show the eight vacuum tubes of that auxiliary group oftubes which is operatively associated with the main group of vacuumtubes shown in Figs. 2 and 3;

Figs. 8 and 9 show the eight vacuum tubes of the other auxiliary groupof tubes which is op eratively associated with the main group of tubesshown in Figs. 4 and 5; while Fig. 10 shows inclusive, should bearranged with group of four hundred other tubes tubes each, namely,

ductors. ing 1449 by way of example, one of the conductors at thatpunching extends to an anode in the taken in connection with the are tobe identied by a tube in the other main group. This arrangement isplainly shown by-the anode designations of the two main groups of tubesin Figs. 2 to 5, inclusive.

Thus, punching '1449 which, at one side is connected to conductor M9, isconnected, on its 200 and 20|, the latter included Within bracket line203. The line 1449 has a thousands-hundreds digit designation of 74 andsince the column of four tubes 'I4XX identification of all the one anodein tube XX49-3 and particularly to the in the group QXX-SBXX which isreserved for the thousands-hundreds identification of the particular onehundred lines row.

To provide these frequencies an auxiliary group of eight forty-anodevacuum tubes is provided for each main group of tubes DUXX-SSXX .to thepositive' side of are connected to the positive side of battery 902 viaconductor 1 |0. Since the cathodes of all tubes in the auxiliary as wellas the main groups are all connected permanently to the filament batterysource 903 via conductors 204 and 205, the grids of the auxiliary tubesare all permanently activated to produce an alternating current flowbetween the cathode and any one or more anodes in their respective tubesas soon as a positive potential of the required value is applied to saidanode or anodes, the frequency of said current being, of course, thesame as that of the source connected to the grid.

Now the grids of all the tubes in each column and row of the two maingroups of tubes are connected via a separate low resistance for eachcolumn and row, to conductor 206 and thence battery 902. On the otherhand, each separate group of grids in a column or row of tubes isconnected via a condenser coupling to an anode in one or two of thetubes in the auxiliary group associated with one or the other,respectively, of the main group of tubes. The order of connection isfour grids in a column or row in a main group of tubes to an anode inone r two of the tubes in the associated auxiliary group whose grids areconnected, respectively, to the frequency sources which, singly or incombination of two, will identify the two digits characterized by thecolumn or row of tubes in the two main groups according to the followingcode:

Numeral frequency code table Hundreds Digit Thousands Tens Units a e i mb I j n c g k o d l p ab ej ij 'm'n ac eg ik mo ad eh il mp bc In jk 'nobd fh c jl np cd ah kl op Thus, as an illustration of the connectionsbetween the grids of the tubes in the two main groups and theanodes ofthe tubes in the two auxiliary groups, consider, for example, the columnof tubes mi to an anode of the second tube 14XX-2 of which is connectedconductor 200 and the row of tubes XXIS to an anode of the third tubeXX49-3 of which is connected conductor 20|. These conductors, it will berecalled, are extensions of the line identifying conductor |49 of line1449. Now the column of tube NXX identifies the thousands-hundredsdigits 74 and, according to the above table, the thousands digit 7requires currents of frequencies b and c for its identification whiledigit 4 requires currents of frequencies e and f for its identification.Accordingly, the grids of by the numbering of the hundreds Y quenciesassigned to pled and connected to the condenser 201 the other side ofwhich is connected to grounded resistance 20E and conductor 209.Conductor 209, on the other hand, has four branches. The first, branch600, is tube B whose grid is connected to frequency source b; thesecond, branch 60|, is connected to anode |5 of tube C whose grid isconnected to frequency source c; the third, branch 100, is connected toanode i8 of tube E whose Vgrid is connected to frequency source e; andthe fourth, branch 10|, is connected to anode |8 of tube F whose grid isconnected to frequency source j. It is obvious that, under properconditions of activation as described below, anode 49 of tube 2 in thecolumn MXX willhave a current passing through it composed of frequenciesb, c, e and f in identification of the thousands-hundreds digits 74.

In the same manner, the grids of the four tubes comprising row XXIS aremultipled and connected to condenser 501 the other side of which isconnected to grounded resistance 508 and conductor 509. Since, accordingto the above table, tens digit 4 is identified by the fre-v quencies iand a' and the units digit 9 by the frequencies o and p, conductor 509likewise has four branches, the first of which, branch 800. is connectedto anode 20 of tube I connected to frequency source i; the second,branch is connected to anode 20 of tube J connected to frequency sourcefi; the third, branch 900, is connected to anode 35 of tube O connectedto frequency source o and the fourth, branch is connected to anode 35 oftube P connected to frequency source p. As in the previous case, in derproper conditions of activation, anode 113 ci tube 3 in row XX49 willpass a current consisting of frequencies i, j, o and p in identificationof the tens and units digits 49.

As noted from the above code, the four auxiliary tubes A to D arereserved for the four frequencies assigned to the thousands digit; thefour tubes E to H are served for the four frethe hundreds digit; thefour tubes I to L are reserved for the four frequencies assigned to thetens digit; and the four tubes M to P are reserved for the fourfrequencies assigned to the units digit. As further noted the anodes ofthe auxiliary tubes, each anode in a group of ten consecutive anodescounting from the bottom upward, is connected to the grids of a columnor row of tubes in the main groups which characterizes one of the digitsidentified in whole or in part by the frequency connected to the grid ofthe auxiliary tube. Since four primary frequencies are used singly or incombinations of two to identify each numerical value of each of the fourdigits, it is clear that each auxiliary tube need not have more thanforty anodes.

The receiving equipment is only schematically indicated in Fig. l sinceall its parts are well known and commercially available. It comprises arelay |0| adapted in any suitable manner to ground the winding side ofthe line cutoff relay |00, a relay |02 which may be operated in anysuitable manner when line identification is to be obtained, and atransformer |04 having the input side of an amplifier |03 connected toits secondary winding. The output side of the amplifier is connected tofour groups of four filtering rectifying circuits of any suitabledeconnected to anode 25 in It will be observed that, in my invention,there is no limit to the number of simultaneous line identications whichcan be type In fact the manner in which the connection 1s extended 1s 0fno controlling 1mp0rtance far as the line identlcation circuit itself isconto this invention other than the fact that what- Cerned, there @an beas many simultaneous ldenever means are usedwill include a relay |0|which will be caused to operate and close a circuit that operates thecut-oil relay |00.

It will b e observed that the identifying conductor |49 has negativepotential applied thereto through the winding of the cut-01T relay CO.This potential is, of course, further applied to the anodes 49 and 14 inthe two tubes '|4XX-2 and XX49-3. The cathode potential from battery903, however, is maintained at slightly less negative value than thatapplied to the identifyment, relay |02 again applied to '|4XX and anodeso that, normally, when the lines are idle, no current will flow throughany of the tubes in the main groups. When, however, a line calls,

be made by those skilled in the art without departing from the spirit ofthe invention as defined Within the scope of the appended claims.

What is claimed is: 1. A calling line ldentication circuit for the linesof merical designation, and means responsive to the application of apotential to the control elements of calling lines for operating theassociated electronic devices to produce an indication of the identityof each of said lines.

on TAB.I, conductor tacts of relay |0|. In the same way, tube 3 in rowXX49 is operated to pass a current between its cathode and such anode,modulated by freassociated vacuum of the four ltering rectiiying units,one for each digit of the linel number. Each rectifying unit selectivelyoperates on the frequency to which it is tuned and results in theoperation of the relay individual to the unit. The number of reing linesfor operating the tubes to produce an indication of the identity of eachof said lines.

3. An identiiicatlon circuit for the lines of a telephone systemcomprising in Acombination a tubes to produce a numerical identiiicationof the line to which said potential was applied.

4. An identication circuit for the lines of a telephone systemcomprising in combination two of electronic devices normally adapted togroups of devices ordinately relative to the numerical designations ofthe lines of the system and electrically coupled to the electrodes ofthe devices of said first two groups, means potential through one ofsaid lines when calling to an electronic device in each of said othertwo whereby said devices are rendered conducting to produce analternating-current of the frequencies determined by the electrodescoupled to said devices, and means selectively responsive'to each of thefrequencies present in the current produced by the operation of saiddevices for identifying the numerical designation of said calling line.

5. An identication circuit for the lines of a telephone systemcomprising in combination two groups of vacuum tubes each having aplurality of anodes, a grid and a cathode with each grid adapted tomodulate a current flow between the cathode and all anodes in accordancewith a specific frequency, two other groups of vacuum tubes disposedcoordinately relative to the numerical designation of the lines of thesystem and having their respective grids electrically coupled to theanodes of the vacuum tubes of said first two groups, means for applyinga signaling potential through one of said lines when calling to an anodeof a tube in each of said two other groups of tubes whereby said tubesare activated to produce an alternating current of the frequenciesdetermined by the grids of the tubes in said first two groups coupled tosaid activated tubes, and means selectively responsive to each of thefrequencies present in the current produced by said activated tubes foridentifying the numerical designation of said line.

6. A calling line identification circuit for the lines of a telephonesystem comprising two main groups of electronic devices havingelectrodes connected to said lines, two auxiliary groups of electronicdevices for each of said main group of devices having electrodesconnected to the grids of the devices in the associated main group andadapted to apply a potential of specific frequency to the grids thereof,means responsive to the application of a potential to the electrodes ofthe devices in the two main groups for operating said devices whereby analternating potential having a plurality of frequencies is produced, andmeansselectively responsive to each frequency for indicating thenumerical designation of said calling line.

'7. A calling line identification circuit for the lines of a telephonesystem comprising in combination two main groups of electronic deviceshaving electrodes connected to said lines, two

auxiliary groups of electronic devices for each of said main group ofdevices having electrodes connected to theI grids of the devices in theassociated main group'and adapted to apply a potential of specificfrequency to the grids thereof, means responsive to the application of apotential to the electrodes of the devices in the two main groups foroperating said devices whereby in response t the alternating potentialon their Arespective grids, an alternating potential is produced throughsaid electrodes, and circuit closing means including settable registersselectively responsive to each of the frequencies in said alternatingpotential for operating said for applying a signaling4 devices andsetting said registers to indicate the identity of said line.

8. A calling line identification circut for the lines of a telephonesystem comprising in combination two main groups of electronic deviceshaving electrodes connected to said lines, two auxiliary groups ofelectronic devices for each of said main group of devices havingelectrodes connected to the grids of the devices in the associated maingroup and adapted to apply a plural frequency alternating potentialthereto, means responsive to the application of a potential to theelectrodes of the line initiating a call for causing the associatedelectronic devices to become operative in producing an alternatingcurrent of the plural frequencies applied to the grids thereof, andmeans selectivelyY responsive to the frequencies present in said currentfor identifying the calling line to which said potential was applied.

9. An identification circuit for the lines of a telephone systemcomprising in combination an identifying conductor for each line,twogroups of electronic devices disposed in coordinate pattern inrelation to the numerical designation of each of the lines in thesystem, each electronic device in each group having a plurality ofelectrodes connected to as many line identifying conductors foridentifying two digits ofthe associated line number and to an electrodein a device of the other group for identifying two other digits of thesame line number, means for applying a signaling potential to theidentifying conductor of one of said lines when calling and,therethrough, to the electrode in a device in each group connectedthereto whereby said devices are activated, to pass a currenttherethrough, means for modulating said current to a plural frequencycurrent in accordance with a frequency allocation to each numeral of adigit in each of the four digits of a line number, and

means selectively responsive to said alternating potential foridentifying the numerical designation of the line to whose identifyingconductor the signaling potential was applied.

l0. An identification circuit for the lines of a telephone systemcomprising in combination with an identifying conductor for each line, arst pair of electronic devices for a group' of said lines, each of saiddevices having an electrode for each line in the group connected to theidentifying conductor thereof, a plurality of other electronic deviceseach having an electrode connected to the grid of a device in said firstpair and adapted to apply a potential of specific frequency thereto inaccordance with a frequency allocation to the digits of the linenumbers, means responsive to the application of a lsignaling potentialto the identifying conductor of a calling line in through, to theelectrodes of the rst pair of devices connected to said conductor foroperating said pair of devices to produce an alternathaving the sameplural frequencies as the potential on the grid thereof, and meansresponsive to the operation of -said first pair of devices foridentifying the conductor to which said signaling potential was applied.

W'ILLIAM A. RHODES.

the group and, there-

